Indicator for synchronous electrical control systems



May 11, 1943- c. F. WEBB ET AL 2,318,727

INDICATOR FOR SYNCHRONOUS ELECTRICAL CONTROL SYSTEMS Filed Feb. 13, 1941 2 Sheets-Sheet 1 Fig. 1. 4

May ll, 1943. c. F. WEBB ET AL INDICATOR FOR SYNCHRONOUS ELECTRICAL CONTROL SYSTEMS 2 Sheets-Sheet 2 Filed Feb. 13, 1941 Fig. 3.

Fig. 5.

UNETE STATES OFFI-QE INDICATOR FOR SYNCHRONOUS ELEC- TRICAL CONTROL SYSTEMS Christopher Frederick Webb and Norman Ernest Brewerton, Uxbridge, England, assignors to Bell Punch Company Limited, London, Eng land, a British company Application February 13, 1941, Serial No. 378,782

in Great Britain February 6,1940

3 Claims. (01. 116-124) This invention relates to synchronous electripointer will receive an angular displacement concal control systems. siderably'greater than that imparted to the ro- One known form of synchronous control systor. tem employs a so-called transmitter at one point In order that the said invention may be clearand a receiver at another point remote from the 1y understood and readily carried into effect the first point, the arrangement being such that same will now be more fully described with refwhen a rotor in the transmitter is rotated erence to the accompanying drawings, in which: through an angle a rotor in the receiver is auto- Fig. l is a front elevation of a part of a rematically caused to rotate through the same ceiver incorporating the invention;

angle. Associated with the receiver is a dial Fig. 2 isa" side view, partly in section, of the and pointer, the latter being directly mounted on receiver shown in Fig. 1, the section being taken or otherwise connected. to the rotor spindle in on the line IIII of Fig. 1;

the receiver and being arranged to move over Fig. 3 is another sectional view taken on the the dial which itself is rotatable about its centre line III-III of Fig. 2;

and is connected to the member or part to be Fig. 4 is a detail view of the means provided controlled. Normally the pointer lies at Zero on for effecting the displacement of the zero-ising the dial but when the rotor in the receiver repointer; and volves in dependence on the rotation of the rotor Fig. 5 is an enlarged view of a portion of Fig. 2. in the transmitter the pointer moves over the In the form of the invention illustrated in the dial, which is graduated in degrees, to indicate accompanying drawings, l indicates the receiver the angle of rotation of the receiver rotor and stator, 2 indicates the receiver rotor and 3 indihence of the transmitter rotor. After the pointer Oates t e spindle of the latter. To the endof has come torest the dial is rotated by actuation the said Sp d e is secured a small pinion 4 meshof suitable hand or power operated means until g W h a t ot Wheel segment 5 Which is its zero point is again aligned with the pointer, carried! y a P n p e 5 haVing One end such operation of the hand or power means servthereof journalled in a front plate I and its other ing also to move the member or part to be conend journalled in the central portion of a trolled through the same angle as that through shaped bracket 8 that is mounted in position on which the dial has been moved and hence through and spaced from the rear face of the said front the same angle as that through which the rotor plate as, for example, by a pair of pins it and in the transmitter was originally moved. spacing washers 9.

The system above described suffers, however, As may be seen from Fig. 2, the receiver stator from the disadvantage that unless the dial is is Ca e by a p ate or frame I2 and the aforemade comparatively large it is difficult to ensure id fr nt p e is arranged o th it i pa e the exact alignment of the pointer with the zero m and is s pported y he plate for on the dial. It is the object of the present invenp by three P l3 P ed t pac tion to overcome this disadvantage in a simple sleeves M (Fig. 3). and eificient manner. To the front plate 1 is secured a graduated According to the invention there is provided, scale plate l5 adjacent to which moves the free in or for a synchronous control system, a reend f a pointer It the other end of which exceiver having a rotor and an angularly displacee s through a t IT in the front plate d is able pointer adapted to be moved. upon displacesecured to the toothed wheel or segment 5. Norment of the rotor through a predetermined angle mally the pointer is is in 3 Vertical D n in and movement transmission means effecting, alignment With h zero on the scale p over a predetermined range, a mechanical mag- When, however, rotation of the receiver rotor nification of the angular movement of the pointer is P u e as a result o tation of the transin relation to that of the rotor for the purpose tter bel, the pointer I6 is swung, owin of observing with greater accuracy the reading the fact that the pinion 4 is meshing with the of the pointer position at or near the zero positoothed wheel or segment 5, away from the zero, tion. Said movement transmission means prefer to the r g t r to t e left (F I), dependerably comprise a driving pin carried by a meming upon the direction of rotation of the receiver ber displaceable angularly with the rotor and a rotor. It will be noted that the receiver rotor forked or slotted member connected with the may be rotated through 360 in either direction pointer anclarranged so that, upon engagement but that, with the gearing employed, the angular of the driving pin with the fork or slot, such movement of the pointer'isconsiderablyless.

Now, as indicated above, unless the scale is made comparatively large, it is diflicult to ensure the exact alignment of the pointer with the zero on the scale when again bringing the parts and the pointer to zero, and, in accordance with the present invention, means is provided whereby a; small rotation of the receiver rotor is adapted, over a range in the vicinity of the zero reading, to produce a comparatively large movement of an indicator or zero-ising pointer over the scale. As illustrated, the said means comprises a pin-andslot mechanism in which a pin is secured to a member or counter-weighted arm 2| movable angularly with the rotor spindle 3 and is adapted for engagement in a V-shaped slot 22 formed in a forked shaped member 23 which is pivotally mounted in position on the frame of the receiver and is provided with a relatively long zero-ising pointer 24 adapted to be moved over the scale plate IS with an enlarged or amplified movement whilst the pointer I6 is in the immediate vicinity of the zero reading. As will be seen, the zeroising pointer, when at zero, overlies the pointer I6 and has its lower end secured to an L-shaped bracket 25 which extends through a slot 26 in the front plate I and is secured to the lower end of the forked shaped member 23 and the latter is carried by a pin 28 having one end journalled in the front plate and its other end journalled in a bracket 29 which is carried by and spaced from the rear face of the front plate, the arrangement being such that, when the zero-ising pointer is at zero, the pin 20 is disposed at the base of the slot and in a parallel-walled portion formed thereat whilst, when receiver rotor is displaced in either direction by even a small amount, the forked member will be displaced to cause a relatively large angular movement to be imparted to the zeroising pointer.

Thus, the operation of the arrangement above described is as follows:

Normally, the pointer I6 and the zeroising pointer 24 are in a vertical position in alignment with the zero reading on the scale. When rotation of the receiver rotor is produced as a result of rotation of the transmitter rotor, the pointers are swung away from the zero in a direction depending on the direction of rotation of the receiver rotor and, during the initial part of the movement of the rotor, the pointers I6 and 24 are displaced differentially so that a comparatively large movement of the pointer 24 over the scale is produced. As soon as, however, the rotor has rotated through an amount, e. g. 10 or 20 degrees, sufficient to cause the pin 20 to disengage the slot in the forked member 23, as is shown by the chain dotted lines in Fig. 4, the pointer 24 will not be further displaced relatively to the scale although the rotor and the pointer I6 may continue to move until movement of the transmitter rotor ceases.

After the receiver rotor has been brought to rest, the receiver stator is rotated by suitable operation of hand or power means, as for instance by a shaft 50 and a worm 5| engaging with a worm wheel 52 attached to the stator, in a direction opposite to that in which the receiver rotor was originally rotated, such rotation serving also to revolve the rotor in the said opposite direction. For this purpose, the receiver stator is rotatably mounted in the mounting constituted by the plate l2. Operation of the hand or power means is continued until the pointers have been restoredto their zero positions and, in this connection, it will be appreciated that an accurate restoration of the rotor to its initial position is made possible by reason of the fact that, as the pointer I6 approaches the zero position, the pin and slot mechanism above described is brought into operation to effect a displacement of the zero-ising pointer 24 under such conditions that a small movement of the rotor produces a comparatively large movement of the zero-ising pointer over the scale until the zero position is reached. Operation of the hand or power means also serves to move the member or part to be controlled, e. g. a gun mounting or other device which it is the purpose of the receiver to control, and when operation of the said means is eventually discontinued, the pointers having been reset at zero, the said member or part will have been moved through precisely the same angle as that through which the transmitter rotor was originally rotated.

The receiver rotor may be moved independently of the transmitter rotor when no current is being supplied to the system and to ensure that the receiver rotor will align itself correctly with the transmitter rotor when the current is switched mitter a switch which can only be operated when the transmitter is in the centre of its normal operating arc. Also, means such as an electrically operated brake may be provided on the receiver so that it is adapted to cause the rotor to be locked to the stator during any movement of the latter when the current is ofi. In the arrangement illustrated, the aforesaid means comprises an arm 30 pivoted at 3| and adapted to be moved by electrically operable means including an armature 32 from the full line position into the dotted line position shown in Fig. 2. At or near its free end the arm is provided with a roller 33 bearing against the free end of a lever 34 which is L-shaped in form and is pivotally mounted in a pair of brackets 35 projecting rearwardly from the front plate 1. Said lever is also provided with an upwardly extending arm 38 terminating in a forked-shaped end having two prongs 39 engaging opposite sides of a flanged brake bobbin 40 which is slidably mounted on the rotor spindle bush 4|. The said brake bobbin bears at one end against the rear surface of the arm 2| and at its other end against a brake spring consisting for example, of an arched spring strip 42 provided with a central opening through which the bush 4| extends and arranged so that the ends there-of bear against the end of the stator The arrangement is such that, in the off position of the brake (shown in full lines in Fig. 2), the prongs 39 lie between the flanged end of the brake bobbin and the spring 42 serves to press the bobbin against arm 2| and thereby frictionally couple the stator to the rotor. When, however, the current is turned on and the switch is operated, the arms 30 and 38 are moved into the dotted line positions shown in Fig. 2 with the result that the brake bobbin is moved endwise to compress the spring 42 and the coupling is broken.

If desired, means may also be provided for visually indicating when the current is on and the brake oif and, for this purpose, a bell-crank lever 45 may be pivotally mounted in position on the rear face of the front plate so that it is adapted to be moved, in opposition to a spring 46, for the purpose of uncovering a signal plate bearing the word on as the brake is moved into the ofi position. Said bellcrank lever is conveniently arranged so that the end 41 thereof is adapted to be displaced by the free end of the arm 30 whilst the other end of the bell-crank lever is displaced to move a flag with the word off engraved thereon from beneath an opening 48 in the front plate so as to reveal the word on on the signal plate.

What we claim and desire to protect by Letters Patent is:

1. In a device of the type described, an angularly movable rotor, a main pointer, means through which the rotor moves said main pointer in accordance with the angular movement of said rotor, an auxiliary pointer, and mechanical amplifying means for effecting magnified angular movements of said auxiliary pointer with respect to said main pointer only when said main pointer is in a predetermined range of its movement, said mechanical amplifying means comprising a driving pin having angular movements substantially proportional to the rotor movements and a pivoted member connected to said auxiliary pointer and provided with a slot receiving said driving pin closely adjacent its pivot to efiect an angular movement of said pivoted member substantially greater than the corresponding driving angular movement of the pin when there exists said closely adjacent relationship of the pin and pivot.

2. In a device of the type described, an angularly movable rotor, a pointer, an index member with which said pointer cooperates, and mechanical amplifying means for efiecting magnified angular movements of said pointer only when said rotor is in a predetermined range of its movement, said mechanical amplifying means comprising a driving pin having angular movements substantially proportional to the rotor movements and a pivoted member connected to said pointer and provided with a slot receiving said driving pin closely adjacent its pivot to efiect an angular movement of said pivoted member substantially greater than the corresponding driving angular movement ofthe pin when there exists said closely adjacent relationship of the pin and pivot.

3. In a device of the type described, an angularly movable rotor, zero indicating means, an index member with which said indicating means cooperates, and mechanical amplifying means for efiecting magnified angular movements of said indicating means only when said rotor i in a predetermined range of its movement, said mechanical amplifying means comprising a driving pin having angular movements substantially proportional to the rotor movements and a pivoted member carrying said indicating mean and provided with a slot receiving said driving pin closely adjacent its pivot to effect an angular movement of said pivoted member substantially greater than the corresponding driving angular movement of the pin when there exists said closely adjacent relationship of the pin and pivot.

CHRISTOPHER FREDERICK WEBB. NORMAN ERNEST BREWERTON. 

